1. Field of the Invention
The present invention relates to a vapor deposition system used for forming a film of a vapor deposition material and a vapor deposition method therefor.
2. Related Background Art
A progress has recently been made in development of an organic electroluminescent (EL) element (OLED). Among organic materials used for the organic EL element, a film of an organic material constituted of a low molecular weight compound is formed mainly by vapor deposition. The vapor deposition is a method of forming a film by heating a vapor deposition material arranged in a vapor depositing source and sticking the evaporated vapor deposition material to an object to be processed.
Japanese Patent Application Laid-Open No. H11-229123 describes a vapor deposition system which includes a crucible for receiving a vapor deposition material, a vapor depositing source shutter, a vapor depositing material recovering tank, and a suction pipe. The vapor depositing source shutter is provided with a function of blocking a flow of the vapor deposition material evaporated from an opening of the crucible in a state of being separated by a few centimeters from above the opening, and configured not to interfere with an evaporation flow of the vapor deposition material in a state of being set in a position shifted from the opening. The position of the vapor depositing source shutter can be controlled by rotating and driving a rotary drive shaft, and flowing of the vapor deposition material evaporated from the crucible to a glass substrate can be permitted or blocked.
The vapor deposition system described in Japanese Patent Application Laid-Open No. H11-229123 can permit or block the flowing of the vapor deposition material evaporated from the crucible to the glass substrate by operating the vapor depositing source shutter. However, since the vapor depositing source shutter is separated from the crucible as described above, the evaporated vapor deposition material continues to leak into a film forming chamber from a separated area above the opening in this state.
The inventors have found that the described technical effects cannot be obtained by the vapor deposition system of Japanese Patent Application Laid-Open No. H11-229123. In other words, there is no big difference between a suction force of a suction pump and a suction force of a vacuum pump for suction in the film forming chamber. Further, the suction force of the suction pump is never much greater than that of the vacuum pump. To compare one end of the suction pipe, i.e., a suction port, with the area above the opening separated from the vapor depositing source shutter, the latter is substantially larger, and it is obvious that the material is not sucked into the suction pipe in most cases but released into the film forming chamber. Thus, the described technical effects cannot be obtained by the vapor deposition system described in Japanese Patent Application Laid-Open No. H11-229123.